Sense
Encyclopedia
Senses are physiological capacities of organism
s that provide inputs for perception
. The senses and their operation, classification, and theory are overlapping topics studied by a variety of fields, most notably neuroscience
, cognitive psychology
(or cognitive science
), and philosophy of perception
. The nervous system
has a specific sensory system
or organ, dedicated to each sense.
Human beings have a multitude of senses. In addition to the traditionally recognized five senses of sight (ophthalmoception), hearing (audioception), taste (gustaoception), smell (olfacoception or olfacception), and touch (tactioception), other senses include temperature (thermoception), kinesthetic sense (proprioception), pain (nociception), balance (equilibrioception) and acceleration (kinesthesioception). What constitutes a sense is a matter of some debate, leading to difficulties in defining what exactly a sense is.
Non-human animals also have receptors to sense the world around them, with degrees of capability varying greatly between species. Humans have a comparatively weak sense of smell, whilst other species may lack one or more of the traditional five senses. Other species may also intake and interpret sensory stimuli
in very different ways. Some species of animals are able to sense the world in a way that humans cannot, with some species able to sense electrical and magnetic field
s, and detect water pressure and currents.
. Humans are considered to have at least five additional senses that include: nociception
(pain); equilibrioception
(balance); proprioception
and kinaesthesia (joint motion and acceleration); sense of time; thermoception
(temperature differences); and possibly an additional weak magnetoception
(direction), and six more if interoceptive senses (see other internal senses below) are also considered.
One commonly recognized categorisation for human senses is as follows: chemoreception; photoreception; mechanoreception; and thermoception
. This categorisation has been criticized as too restrictive, however, as it does not include categories for accepted senses such as the sense of time and sense of pain
.
Non-human animals may possess senses that are absent in humans, such as electroreception
and detection of polarized light.
A broadly acceptable definition of a sense would be "A system that consists of a group of sensory cell types that responds to a specific physical phenomenon, and that corresponds to a particular group of regions within the brain where the signal
s are received and interpreted." Disputes about the number of senses typically arise around the classification of the various cell types and their mapping
to regions of the brain.
or vision is the ability of the eye(s) to focus and detect images of visible light
on photoreceptors in the retina
of each eye that generates electrical nerve impulses
for varying colors, hues, and brightness. There are two types of photoreceptors: rods
and cones
. Rods are very sensitive to light, but do not distinguish colors. Cones distinguish colors, but are less sensitive to dim light. There is some disagreement as to whether this constitutes one, two or three senses. Neuroanatomists generally regard it as two senses, given that different receptors are responsible for the perception of color and brightness. Some argue that stereopsis
, the perception of depth using both eyes, also constitutes a sense, but it is generally regarded as a cognitive (that is, post-sensory) function of the visual cortex
of the brain where patterns and objects in images
are recognized and interpreted based on previously learned information, This is called visual memory. The inability to see is called blindness
.
Blindness may result from damage to the eyeball, especially to the retina, damage to the optic nerve that connects each eye to the brain, and/or from stroke (infarcts in the brain). Temporary or permanent blindness can be caused by poisons or medications.
or audition is the sense of sound
perception. Hearing is all about vibration. Mechanoreceptors turn motion into electrical nerve pulses, which are located in the inner ear. Since sound is vibrations propagating through a medium such as air, the detection of these vibrations, that is the sense of the hearing, is a mechanical sense because these vibrations are mechanically conducted from the eardrum through a series of tiny bones to hair-like fibers in the inner ear
, which detect mechanical motion of the fibers within a range of about 20 to 20,000 hertz
, with substantial variation between individuals. Hearing at high frequencies declines with an increase in age. Inability to hear is called deafness
. Sound can also be detected as vibrations conducted through the body by tactition. Lower frequencies than can be heard are detected this way.
(or, the more formal term, gustation; adjectival form: "gustatory") is one of the traditional five senses. It refers to the ability to detect the flavor of substances such as food, certain minerals, and poisons, etc. Humans receive tastes through sensory organs called taste buds, or gustatory calyculi, concentrated on the upper surface of the tongue. The sensation of taste can be categorized into six basic tastes: sweetness, bitterness, sourness, saltiness, umami and calcium . The recognition and awareness of umami is a relatively recent development in Western cuisine. MSG produces a strong umami taste so much so that it is said to taste soapy by itself.
or olfaction is the other "chemical" sense. Unlike taste, there are hundreds of olfactory receptors (388 according to one source), each binding to a particular molecular feature. Odor molecules possess a variety of features and, thus, excite specific receptors more or less strongly. This combination of excitatory signals from different receptors makes up what we perceive as the molecule's smell. In the brain, olfaction is processed by the olfactory system
. Olfactory receptor neuron
s in the nose
differ from most other neurons in that they die and regenerate on a regular basis. The inability to smell is called anosmia
. Some neurons in the nose are specialized to detect pheromone
s.
, is a perception resulting from activation of neural receptors, generally in the skin
including hair follicle
s, but also in the tongue
, throat
, and mucosa
. A variety of pressure
receptors respond to variations in pressure (firm, brushing, sustained, etc.). The touch sense of itch
ing caused by insect bites or allergies involves special itch-specific neurons in the skin and spinal cord. The loss or impairment of the ability to feel anything touched is called tactile anesthesia
. Paresthesia
is a sensation of tingling, pricking, or numbness of the skin that may result from nerve damage and may be permanent or temporary.
, equilibrioception
, or vestibular sense is the sense that allows an organism to sense body movement, direction, and acceleration, and to attain and maintain postural equilibrium and balance. The organ of equilibrioception is the vestibular labyrinthine system found in both of the inner ear
s. In technical terms, this organ is responsible for two senses of angular momentum
acceleration and linear acceleration (which also senses gravity), but they are known together as equilibrioception.
The vestibular nerve
conducts information from sensory receptors in three ampulla
that sense motion of fluid in three semicircular canals caused by three-dimensional rotation of the head. The vestibular nerve also conducts information from the utricle and the saccule
, which contain hair-like sensory receptors that bend under the weight of otolith
s (which are small crystals of calcium carbonate
) that provide the inertia needed to detect head rotation, linear acceleration, and the direction of gravitational force.
is the sense of heat and the absence of heat (cold) by the skin
and including internal skin passages, or, rather, the heat flux
(the rate of heat flow) in these areas. There are specialized receptors for cold (declining temperature) and to heat. The cold receptors play an important part in the dog's sense of smell, telling wind direction. The heat receptors are sensitive to infrared radiation and can occur in specialized organs for instance in pit vipers. The thermoceptors in the skin are quite different from the homeostatic
thermoceptors in the brain (hypothalamus
), which provide feedback on internal body temperature.
, the kinesthetic sense, provides the parietal cortex
of the brain with information on the relative positions of the parts of the body. Neurologists test this sense by telling patients to close their eyes and touch their own nose with the tip of a finger. Assuming proper proprioceptive function, at no time will the person lose awareness of where the hand actually is, even though it is not being detected by any of the other senses. Proprioception and touch are related in subtle ways, and their impairment results in surprising and deep deficits in perception and action.
(physiological pain
) signals nerve-damage or damage to tissue. The three types of pain receptors are cutaneous (skin), somatic (joints and bones), and visceral (body organs). It was previously believed that pain was simply the overloading of pressure receptors, but research in the first half of the 20th century indicated that pain is a distinct phenomenon that intertwines with all of the other senses, including touch. Pain was once considered an entirely subjective experience, but recent studies show that pain is registered in the anterior cingulate gyrus of the brain. The main function of pain is to warn us about dangers. For example, humans avoid touching a sharp needle or hot object or extending an arm beyond a safe limit because it hurts, and thus is dangerous. Without pain, people could do many dangerous things without realizing it.
s and cetacea
ns, have the ability to determine orientation to other objects through interpretation of reflected sound (like sonar
). They most often use this to navigate through poor lighting conditions or to identify and track prey. There is currently an uncertainty whether this is simply an extremely developed post-sensory interpretation of auditory perceptions or it actually constitutes a separate sense. Resolution of the issue will require brain scans of animals while they actually perform echolocation
, a task that has proven difficult in practice.
Blind people report they are able to navigate and in some cases identify an object by interpreting reflected sounds (esp. their own footsteps), a phenomenon known as human echolocation
.
s have olfactory receptors on their antennae
.
s, reptile
s, mammals) have a vomeronasal organ
that is connected with the mouth cavity. In mammals it is mainly used to detect pheromones to mark their territory, trails, and sexual state. Reptiles like snake
s and monitor lizard
s make extensive use of it as a smelling organ by transferring scent molecules to the vomeronasal organ with the tips of the forked tongue. In mammals, it is often associated with a special behavior called flehmen characterized by uplifting of the lips. The organ is vestigial in humans
, because associated neurons have not been found that give any sensory input in humans.
and butterflies have taste organs on their feet, allowing them to taste anything they land on. Catfish
have taste organs across their entire bodies, and can taste anything they touch, including chemicals in the water.
, a reflective membrane that optimizes the image.
Pitvipers
, pythons and some boas have organs that allow them to detect infrared
light, such that these snakes are able to sense the body heat of their prey. The common vampire bat
may also have an infrared sensor on its nose. It has been found that birds and some other animals are tetrachromats and have the ability to see in the ultraviolet
down to 300 nanometers. Bees and dragonflies are also able to see in the ultraviolet.
) that works very differently from the mammalian's semi-circular canals.
(roughly 6th century BC), as five horses drawing the "chariot
" of the body, guided by the mind as "chariot driver".
Depictions of the five traditional senses as allegory
became a popular subject for seventeenth-century artists, especially among Dutch
and Flemish Baroque painters. A typical example is Gérard de Lairesse
's Allegory of the Five Senses (1668), in which each of the figures in the main group allude to a sense: Sight is the reclining boy with a convex mirror, hearing is the cupid
-like boy with a triangle
, smell is represented by the girl with flowers, taste is represented by the woman with the fruit, and touch is represented by the woman holding the bird.
Organism
In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...
s that provide inputs for perception
Perception
Perception is the process of attaining awareness or understanding of the environment by organizing and interpreting sensory information. All perception involves signals in the nervous system, which in turn result from physical stimulation of the sense organs...
. The senses and their operation, classification, and theory are overlapping topics studied by a variety of fields, most notably neuroscience
Neuroscience
Neuroscience is the scientific study of the nervous system. Traditionally, neuroscience has been seen as a branch of biology. However, it is currently an interdisciplinary science that collaborates with other fields such as chemistry, computer science, engineering, linguistics, mathematics,...
, cognitive psychology
Cognitive psychology
Cognitive psychology is a subdiscipline of psychology exploring internal mental processes.It is the study of how people perceive, remember, think, speak, and solve problems.Cognitive psychology differs from previous psychological approaches in two key ways....
(or cognitive science
Cognitive science
Cognitive science is the interdisciplinary scientific study of mind and its processes. It examines what cognition is, what it does and how it works. It includes research on how information is processed , represented, and transformed in behaviour, nervous system or machine...
), and philosophy of perception
Philosophy of perception
The philosophy of perception is concerned with the nature of perceptual experience and the status of perceptual data, in particular how they relate to beliefs about, or knowledge of, the world. Any explicit account of perception requires a commitment to one of a variety of ontological or...
. The nervous system
Nervous system
The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous...
has a specific sensory system
Sensory system
A sensory system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory receptors, neural pathways, and parts of the brain involved in sensory perception. Commonly recognized sensory systems are those for vision, hearing, somatic...
or organ, dedicated to each sense.
Human beings have a multitude of senses. In addition to the traditionally recognized five senses of sight (ophthalmoception), hearing (audioception), taste (gustaoception), smell (olfacoception or olfacception), and touch (tactioception), other senses include temperature (thermoception), kinesthetic sense (proprioception), pain (nociception), balance (equilibrioception) and acceleration (kinesthesioception). What constitutes a sense is a matter of some debate, leading to difficulties in defining what exactly a sense is.
Non-human animals also have receptors to sense the world around them, with degrees of capability varying greatly between species. Humans have a comparatively weak sense of smell, whilst other species may lack one or more of the traditional five senses. Other species may also intake and interpret sensory stimuli
Stimulus (psychology)
In psychology, stimuli are energy patterns which are registered by the senses. In behaviorism and related stimulus–response theories, stimuli constitute the basis for behavior, whereas in perceptual psychology they constitute the basis for perception.In the second half of the 19th century, the...
in very different ways. Some species of animals are able to sense the world in a way that humans cannot, with some species able to sense electrical and magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
s, and detect water pressure and currents.
Definition
There is no firm agreement among neurologists as to the number of senses because of differing definitions of what constitutes a sense. One definition states that an exteroceptive sense is a faculty by which outside stimuli are perceived. The traditional five senses are sight, hearing, touch, smell and taste, a classification attributed to AristotleAristotle
Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...
. Humans are considered to have at least five additional senses that include: nociception
Nociception
Nociception is defined as "the neural processes of encoding and processing noxious stimuli." It is the afferent activity produced in the peripheral and central nervous system by stimuli that have the potential to damage tissue...
(pain); equilibrioception
Equilibrioception
Equilibrioception or sense of balance is one of the physiological senses. It helps prevent humans and animals from falling over when walking or standing still. Balance is the result of a number of body systems working together: the eyes , ears and the body's sense of where it is in space ideally...
(balance); proprioception
Proprioception
Proprioception , from Latin proprius, meaning "one's own" and perception, is the sense of the relative position of neighbouring parts of the body and strength of effort being employed in movement...
and kinaesthesia (joint motion and acceleration); sense of time; thermoception
Thermoception
Thermoception or thermoreception is the sense by which an organism perceives temperature. The details of how temperature receptors work are still being investigated. Ciliopathy is associated with decreased ability to sense heat, thus cilia may aid in the process...
(temperature differences); and possibly an additional weak magnetoception
Magnetoception
Magnetoception is the ability to detect a magnetic field to perceive direction, altitude or location. This sense plays a role in the navigational abilities of several animal species and has been postulated as a method for animals to develop regional maps.Magnetoception is most commonly observed in...
(direction), and six more if interoceptive senses (see other internal senses below) are also considered.
One commonly recognized categorisation for human senses is as follows: chemoreception; photoreception; mechanoreception; and thermoception
Thermoception
Thermoception or thermoreception is the sense by which an organism perceives temperature. The details of how temperature receptors work are still being investigated. Ciliopathy is associated with decreased ability to sense heat, thus cilia may aid in the process...
. This categorisation has been criticized as too restrictive, however, as it does not include categories for accepted senses such as the sense of time and sense of pain
Pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
.
Non-human animals may possess senses that are absent in humans, such as electroreception
Electroreception
Electroreception is the biological ability to perceive natural electrical stimuli. It has been observed only in aquatic or amphibious animals, since water is a much better conductor than air. Electroreception is used in electrolocation and for electrocommunication.- Overview :Electroreception is...
and detection of polarized light.
A broadly acceptable definition of a sense would be "A system that consists of a group of sensory cell types that responds to a specific physical phenomenon, and that corresponds to a particular group of regions within the brain where the signal
Signalling theory
Within evolutionary biology, signalling theory is a body of theoretical work examining communication between individuals. The central question is when organisms with conflicting interests should be expected to communicate "honestly"...
s are received and interpreted." Disputes about the number of senses typically arise around the classification of the various cell types and their mapping
Mind map
A mind map is a diagram used to represent words, ideas, tasks, or other items linked to and arranged around a central key word or idea. Especially in British English, the terms spidergram and spidergraph are more common, but they can cause confusion with the term spider diagram used in mathematics...
to regions of the brain.
Sight
SightVisual perception
Visual perception is the ability to interpret information and surroundings from the effects of visible light reaching the eye. The resulting perception is also known as eyesight, sight, or vision...
or vision is the ability of the eye(s) to focus and detect images of visible light
Light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...
on photoreceptors in the retina
Retina
The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical...
of each eye that generates electrical nerve impulses
Action potential
In physiology, an action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and...
for varying colors, hues, and brightness. There are two types of photoreceptors: rods
Rod cell
Rod cells, or rods, are photoreceptor cells in the retina of the eye that can function in less intense light than can the other type of visual photoreceptor, cone cells. Named for their cylindrical shape, rods are concentrated at the outer edges of the retina and are used in peripheral vision. On...
and cones
Cone cell
Cone cells, or cones, are photoreceptor cells in the retina of the eye that are responsible for color vision; they function best in relatively bright light, as opposed to rod cells that work better in dim light. If the retina is exposed to an intense visual stimulus, a negative afterimage will be...
. Rods are very sensitive to light, but do not distinguish colors. Cones distinguish colors, but are less sensitive to dim light. There is some disagreement as to whether this constitutes one, two or three senses. Neuroanatomists generally regard it as two senses, given that different receptors are responsible for the perception of color and brightness. Some argue that stereopsis
Stereopsis
Stereopsis refers to impression of depth that is perceived when a scene is viewed with both eyes by someone with normal binocular vision. Binocular viewing of a scene creates two slightly different images of the scene in the two eyes due the the eyes' different positions on the head...
, the perception of depth using both eyes, also constitutes a sense, but it is generally regarded as a cognitive (that is, post-sensory) function of the visual cortex
Visual cortex
The visual cortex of the brain is the part of the cerebral cortex responsible for processing visual information. It is located in the occipital lobe, in the back of the brain....
of the brain where patterns and objects in images
Real image
In optics, a real image is a representation of an object in which the perceived location is actually a point of convergence of the rays of light that make up the image. If a screen is placed in the plane of a real image the image will generally become visible on the screen...
are recognized and interpreted based on previously learned information, This is called visual memory. The inability to see is called blindness
Blindness
Blindness is the condition of lacking visual perception due to physiological or neurological factors.Various scales have been developed to describe the extent of vision loss and define blindness...
.
Blindness may result from damage to the eyeball, especially to the retina, damage to the optic nerve that connects each eye to the brain, and/or from stroke (infarcts in the brain). Temporary or permanent blindness can be caused by poisons or medications.
Hearing
HearingHearing (sense)
Hearing is the ability to perceive sound by detecting vibrations through an organ such as the ear. It is one of the traditional five senses...
or audition is the sense of sound
Sound
Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations.-Propagation of...
perception. Hearing is all about vibration. Mechanoreceptors turn motion into electrical nerve pulses, which are located in the inner ear. Since sound is vibrations propagating through a medium such as air, the detection of these vibrations, that is the sense of the hearing, is a mechanical sense because these vibrations are mechanically conducted from the eardrum through a series of tiny bones to hair-like fibers in the inner ear
Inner ear
The inner ear is the innermost part of the vertebrate ear. In mammals, it consists of the bony labyrinth, a hollow cavity in the temporal bone of the skull with a system of passages comprising two main functional parts:...
, which detect mechanical motion of the fibers within a range of about 20 to 20,000 hertz
Hertz
The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....
, with substantial variation between individuals. Hearing at high frequencies declines with an increase in age. Inability to hear is called deafness
Hearing impairment
-Definition:Deafness is the inability for the ear to interpret certain or all frequencies of sound.-Environmental Situations:Deafness can be caused by environmental situations such as noise, trauma, or other ear defections...
. Sound can also be detected as vibrations conducted through the body by tactition. Lower frequencies than can be heard are detected this way.
Taste
TasteTaste
Taste is one of the traditional five senses. It refers to the ability to detect the flavor of substances such as food, certain minerals, and poisons, etc....
(or, the more formal term, gustation; adjectival form: "gustatory") is one of the traditional five senses. It refers to the ability to detect the flavor of substances such as food, certain minerals, and poisons, etc. Humans receive tastes through sensory organs called taste buds, or gustatory calyculi, concentrated on the upper surface of the tongue. The sensation of taste can be categorized into six basic tastes: sweetness, bitterness, sourness, saltiness, umami and calcium . The recognition and awareness of umami is a relatively recent development in Western cuisine. MSG produces a strong umami taste so much so that it is said to taste soapy by itself.
Smell
SmellOlfaction
Olfaction is the sense of smell. This sense is mediated by specialized sensory cells of the nasal cavity of vertebrates, and, by analogy, sensory cells of the antennae of invertebrates...
or olfaction is the other "chemical" sense. Unlike taste, there are hundreds of olfactory receptors (388 according to one source), each binding to a particular molecular feature. Odor molecules possess a variety of features and, thus, excite specific receptors more or less strongly. This combination of excitatory signals from different receptors makes up what we perceive as the molecule's smell. In the brain, olfaction is processed by the olfactory system
Olfactory system
The olfactory system is the sensory system used for olfaction, or the sense of smell. Most mammals and reptiles have two distinct parts to their olfactory system: a main olfactory system and an accessory olfactory system. The main olfactory system detects volatile, airborne substances, while the...
. Olfactory receptor neuron
Olfactory receptor neuron
An olfactory receptor neuron , also called an olfactory sensory neuron , is a transduction cell within the olfactory system. J. Rospars, Dendritic integration in olfactory sensory neurons: a steady-state analysis of how the neuron structure and neuron environment influence the coding of odor...
s in the nose
Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...
differ from most other neurons in that they die and regenerate on a regular basis. The inability to smell is called anosmia
Anosmia
Anosmia is a lack of functioning olfaction, or in other words, an inability to perceive odors. Anosmia may be either temporary or permanent. A related term, hyposmia, refers to a decreased ability to smell, while hyperosmia refers to an increased ability to smell. Some people may be anosmic for one...
. Some neurons in the nose are specialized to detect pheromone
Pheromone
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...
s.
Touch
Touch or somatosensory, also called tactition or mechanoreceptionMechanoreceptor
A mechanoreceptor is a sensory receptor that responds to mechanical pressure or distortion. There are four main types in the glabrous skin of humans: Pacinian corpuscles, Meissner's corpuscles, Merkel's discs, and Ruffini corpuscles...
, is a perception resulting from activation of neural receptors, generally in the skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
including hair follicle
Hair follicle
A hair follicle is a skin organ that produces hair. Hair production occurs in phases, including a growth phase , and cessation phase , and a rest phase . Stem cells are principally responsible for the production of hair....
s, but also in the tongue
Tongue
The tongue is a muscular hydrostat on the floors of the mouths of most vertebrates which manipulates food for mastication. It is the primary organ of taste , as much of the upper surface of the tongue is covered in papillae and taste buds. It is sensitive and kept moist by saliva, and is richly...
, throat
Throat
In vertebrate anatomy, the throat is the anterior part of the neck, in front of the vertebral column. It consists of the pharynx and larynx...
, and mucosa
Mucous membrane
The mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. They line cavities that are exposed to the external environment and internal organs...
. A variety of pressure
Pressure
Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
receptors respond to variations in pressure (firm, brushing, sustained, etc.). The touch sense of itch
Itch
Itch is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to classify it as any one type of sensory experience. Modern science has shown that itch has many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response...
ing caused by insect bites or allergies involves special itch-specific neurons in the skin and spinal cord. The loss or impairment of the ability to feel anything touched is called tactile anesthesia
Anesthesia
Anesthesia, or anaesthesia , traditionally meant the condition of having sensation blocked or temporarily taken away...
. Paresthesia
Paresthesia
Paresthesia , spelled "paraesthesia" in British English, is a sensation of tingling, burning, pricking, or numbness of a person's skin with no apparent long-term physical effect. It is more generally known as the feeling of "pins and needles" or of a limb "falling asleep"...
is a sensation of tingling, pricking, or numbness of the skin that may result from nerve damage and may be permanent or temporary.
Balance and acceleration
BalanceBalance (ability)
In biomechanics, balance is an ability to maintain the center of gravity of a body within the base of support with minimal postural sway. When exercising the ability to balance, one is said to be balancing....
, equilibrioception
Equilibrioception
Equilibrioception or sense of balance is one of the physiological senses. It helps prevent humans and animals from falling over when walking or standing still. Balance is the result of a number of body systems working together: the eyes , ears and the body's sense of where it is in space ideally...
, or vestibular sense is the sense that allows an organism to sense body movement, direction, and acceleration, and to attain and maintain postural equilibrium and balance. The organ of equilibrioception is the vestibular labyrinthine system found in both of the inner ear
Inner ear
The inner ear is the innermost part of the vertebrate ear. In mammals, it consists of the bony labyrinth, a hollow cavity in the temporal bone of the skull with a system of passages comprising two main functional parts:...
s. In technical terms, this organ is responsible for two senses of angular momentum
Angular momentum
In physics, angular momentum, moment of momentum, or rotational momentum is a conserved vector quantity that can be used to describe the overall state of a physical system...
acceleration and linear acceleration (which also senses gravity), but they are known together as equilibrioception.
The vestibular nerve
Vestibular nerve
The vestibular nerve is one of the two branches of the Vestibulocochlear nerve . It goes to the semicircular canals via the vestibular ganglion...
conducts information from sensory receptors in three ampulla
Osseous ampullae
The bony semicircular canals are three in number, superior, posterior, and lateral, and are situated above and behind the vestibule. They are unequal in length, compressed from side to side, and each describes the greater part of a circle. Each measures about 0.8 mm...
that sense motion of fluid in three semicircular canals caused by three-dimensional rotation of the head. The vestibular nerve also conducts information from the utricle and the saccule
Saccule
The saccule is a bed of sensory cells situated in the inner ear. The saccule translates head movements into neural impulses which the brain can interpret. The saccule is sensitive to linear translations of the head, specifically movements up and down...
, which contain hair-like sensory receptors that bend under the weight of otolith
Otolith
An otolith, , also called statoconium or otoconium is a structure in the saccule or utricle of the inner ear, specifically in the vestibular labyrinth of vertebrates. The saccule and utricle, in turn, together make the otolith organs. They are sensitive to gravity and linear acceleration...
s (which are small crystals of calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
) that provide the inertia needed to detect head rotation, linear acceleration, and the direction of gravitational force.
Temperature
ThermoceptionThermoception
Thermoception or thermoreception is the sense by which an organism perceives temperature. The details of how temperature receptors work are still being investigated. Ciliopathy is associated with decreased ability to sense heat, thus cilia may aid in the process...
is the sense of heat and the absence of heat (cold) by the skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
and including internal skin passages, or, rather, the heat flux
Heat flux
Heat flux or thermal flux is the rate of heat energy transfer through a given surface. The SI derived unit of heat rate is joule per second, or watt. Heat flux is the heat rate per unit area. In SI units, heat flux is measured in W/m2]. Heat rate is a scalar quantity, while heat flux is a vectorial...
(the rate of heat flow) in these areas. There are specialized receptors for cold (declining temperature) and to heat. The cold receptors play an important part in the dog's sense of smell, telling wind direction. The heat receptors are sensitive to infrared radiation and can occur in specialized organs for instance in pit vipers. The thermoceptors in the skin are quite different from the homeostatic
Homeostasis
Homeostasis is the property of a system that regulates its internal environment and tends to maintain a stable, constant condition of properties like temperature or pH...
thermoceptors in the brain (hypothalamus
POAH
POAH is an acronym for preoptic anterior hypothalamus, the part of the brain that senses core body temperature and regulates it to about 98.6 F.-References:' -- Method for Heating the Preoptic Anterior Hypothalamus-External links:*...
), which provide feedback on internal body temperature.
Kinesthetic sense
ProprioceptionProprioception
Proprioception , from Latin proprius, meaning "one's own" and perception, is the sense of the relative position of neighbouring parts of the body and strength of effort being employed in movement...
, the kinesthetic sense, provides the parietal cortex
Parietal lobe
The parietal lobe is a part of the Brain positioned above the occipital lobe and behind the frontal lobe.The parietal lobe integrates sensory information from different modalities, particularly determining spatial sense and navigation. For example, it comprises somatosensory cortex and the...
of the brain with information on the relative positions of the parts of the body. Neurologists test this sense by telling patients to close their eyes and touch their own nose with the tip of a finger. Assuming proper proprioceptive function, at no time will the person lose awareness of where the hand actually is, even though it is not being detected by any of the other senses. Proprioception and touch are related in subtle ways, and their impairment results in surprising and deep deficits in perception and action.
Pain
NociceptionNociception
Nociception is defined as "the neural processes of encoding and processing noxious stimuli." It is the afferent activity produced in the peripheral and central nervous system by stimuli that have the potential to damage tissue...
(physiological pain
Pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
) signals nerve-damage or damage to tissue. The three types of pain receptors are cutaneous (skin), somatic (joints and bones), and visceral (body organs). It was previously believed that pain was simply the overloading of pressure receptors, but research in the first half of the 20th century indicated that pain is a distinct phenomenon that intertwines with all of the other senses, including touch. Pain was once considered an entirely subjective experience, but recent studies show that pain is registered in the anterior cingulate gyrus of the brain. The main function of pain is to warn us about dangers. For example, humans avoid touching a sharp needle or hot object or extending an arm beyond a safe limit because it hurts, and thus is dangerous. Without pain, people could do many dangerous things without realizing it.
Other internal senses
An internal sense or interoception is "any sense that is normally stimulated from within the body". These involve numerous sensory receptors in internal organs, such as stretch receptors that are neurologically linked to the brain.- Pulmonary stretch receptorsPulmonary stretch receptorsPulmonary stretch receptors are mechanoreceptors found in the lungs.When the lung expands, the receptors imitate the Hering-Breuer reflex, which reduces the respiratory rate...
are found in the lungs and control the respiratory rateRespiratory rateRespiratory rate is also known by respiration rate, pulmonary ventilation rate, ventilation rate, or breathing frequency is the number of breaths taken within a set amount of time, typically 60 seconds....
. - Peripheral chemoreceptorsPeripheral chemoreceptorsPeripheral chemoreceptors act principally to detect variation of the oxygen concentration in the arterial blood, whilst also monitoring arterial carbon dioxide and pH. They are located in the aortic body and carotid body, on the arch of the aorta and on the common carotid artery, respectively. The...
in the brain monitor the carbon dioxide and oxygen levels in the brain to give a feeling of suffocationSuffocationSuffocation is the process of Asphyxia.Suffocation may also refer to:* Suffocation , an American death metal band* "Suffocation", a song on Morbid Angel's debut album, Altars of Madness...
if carbon dioxide levels get too high. - The chemoreceptor trigger zoneChemoreceptor trigger zoneThe chemoreceptor trigger zone , is an area of the medulla that receives inputs from blood-borne drugs or hormones, and communicates with the vomiting center, to initiate vomiting. The CTZ is close to the area postrema on the floor of the fourth ventricle and is outside of the blood-brain barrier...
is an area of the medullaMedulla oblongataThe medulla oblongata is the lower half of the brainstem. In discussions of neurology and similar contexts where no ambiguity will result, it is often referred to as simply the medulla...
in the brain that receives inputs from bloodBloodBlood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
-borne drugDrugA drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...
s or hormoneHormoneA hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...
s, and communicates with the vomiting center. - Chemoreceptors in the circulatory system also measure salt levels and prompt thirst if they get too high (they can also respond to high sugar levels in diabetics).
- Cutaneous receptorCutaneous receptorA cutaneous receptor is a type of sensory receptor found in the dermis or epidermis. They are a part of the somatosensory system. Cutaneous receptors include e.g...
s in the skin not only respond to touch, pressure, and temperature, but also respond to vasodilation in the skin such as blushingBlushingBlushing refers to the involuntary reddening of a person's face due to embarrassment or emotional stress, though it has been known to come from being lovestruck, or from some kind of romantic stimulation. It is thought that blushing is the result of an overactive sympathetic nervous system...
. - Stretch receptors in the gastrointestinal tractGastrointestinal tractThe human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....
sense gas distension that may result in colic pain. - Stimulation of sensory receptors in the esophagusEsophagusThe esophagus is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. During swallowing, food passes from the mouth through the pharynx into the esophagus and travels via peristalsis to the stomach...
result in sensations felt in the throat when swallowingSwallowingSwallowing, known scientifically as deglutition, is the process in the human or animal body that makes something pass from the mouth, to the pharynx, and into the esophagus, while shutting the epiglottis. If this fails and the object goes through the trachea, then choking or pulmonary aspiration...
, vomitingVomitingVomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
, or during acid reflux. - Sensory receptors in pharynxPharynxThe human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...
mucosa, similar to touch receptors in the skin, sense foreign objects such as food that may result in a gag reflexGag reflexThe pharyngeal reflex or gag reflex is a reflex contraction of the back of the throat, evoked by touching the soft palate or sometimes the back of the tongue. It prevents something from entering the throat except as part of normal swallowing and helps prevent choking...
and corresponding gagging sensation. - Stimulation of sensory receptors in the urinary bladderUrinary bladderThe urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...
and rectumRectumThe rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...
may result in sensations of fullness. - Stimulation of stretch sensors that sense dilation of various blood vessels may result in pain, for example headache caused by vasodilation of brain arteries.
Analogous to human senses
Other living organisms have receptors to sense the world around them, including many of the senses listed above for humans. However, the mechanisms and capabilities vary widely.Echolocation
Certain animals, including batBat
Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...
s and cetacea
Cetacea
The order Cetacea includes the marine mammals commonly known as whales, dolphins, and porpoises. Cetus is Latin and is used in biological names to mean "whale"; its original meaning, "large sea animal", was more general. It comes from Ancient Greek , meaning "whale" or "any huge fish or sea...
ns, have the ability to determine orientation to other objects through interpretation of reflected sound (like sonar
Sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...
). They most often use this to navigate through poor lighting conditions or to identify and track prey. There is currently an uncertainty whether this is simply an extremely developed post-sensory interpretation of auditory perceptions or it actually constitutes a separate sense. Resolution of the issue will require brain scans of animals while they actually perform echolocation
Animal echolocation
Echolocation, also called biosonar, is the biological sonar used by several kinds of animals.Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects...
, a task that has proven difficult in practice.
Blind people report they are able to navigate and in some cases identify an object by interpreting reflected sounds (esp. their own footsteps), a phenomenon known as human echolocation
Human echolocation
Human echolocation is the ability of humans to detect objects in their environment by sensing echoes from those objects. By actively creating sounds – for example, by tapping their canes, lightly stomping their foot or making clicking noises with their mouths – people trained to orientate with...
.
Smell
Most non-human mammals have a much keener sense of smell than humans, although the mechanism is similar. Sharks combine their keen sense of smell with timing to determine the direction of a smell. They follow the nostril that first detected the smell. InsectInsect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s have olfactory receptors on their antennae
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
.
Vomeronasal organ
Many animals (salamanderSalamander
Salamander is a common name of approximately 500 species of amphibians. They are typically characterized by a superficially lizard-like appearance, with their slender bodies, short noses, and long tails. All known fossils and extinct species fall under the order Caudata, while sometimes the extant...
s, reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
s, mammals) have a vomeronasal organ
Vomeronasal organ
The vomeronasal organ , or Jacobson's organ, is an auxiliary olfactory sense organ that is found in many animals. It was discovered by Frederik Ruysch and later by Ludwig Jacobson in 1813....
that is connected with the mouth cavity. In mammals it is mainly used to detect pheromones to mark their territory, trails, and sexual state. Reptiles like snake
Snake
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
s and monitor lizard
Monitor lizard
Monitor lizards are usually large reptiles, although some can be as small as in length. They have long necks, powerful tails and claws, and well-developed limbs. Most species are terrestrial, but arboreal and semiaquatic monitors are also known...
s make extensive use of it as a smelling organ by transferring scent molecules to the vomeronasal organ with the tips of the forked tongue. In mammals, it is often associated with a special behavior called flehmen characterized by uplifting of the lips. The organ is vestigial in humans
Human vestigiality
In the context of human evolution, human vestigiality involves those characters occurring in the human species that are considered vestigial—in other words having lost all or most of their original function through evolution...
, because associated neurons have not been found that give any sensory input in humans.
Taste
FliesFließ
Fließ is a municipality in the Landeck district and is located5 km south of Landeck on the upper course of the Inn River. It has 9 hamlets and was already populated at the roman age; the village itself was founded around the 6th century. After a conflagration in 1933 Fließ was restored more...
and butterflies have taste organs on their feet, allowing them to taste anything they land on. Catfish
Catfish
Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...
have taste organs across their entire bodies, and can taste anything they touch, including chemicals in the water.
Vision
Cats have the ability to see in low light due to muscles surrounding their irises to contract and expand pupils as well as the tapetum lucidumTapetum lucidum
The tapetum lucidum is a layer of tissue in the eye of many vertebrate animals....
, a reflective membrane that optimizes the image.
Pitvipers
Crotalinae
The Crotalinae, commonly known as "pit vipers" or crotaline snakes, are a subfamily of venomous vipers found in Asia and the Americas. They are distinguished by the presence of a heat-sensing pit organ located between the eye and the nostril on either side of the head...
, pythons and some boas have organs that allow them to detect infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
light, such that these snakes are able to sense the body heat of their prey. The common vampire bat
Common Vampire Bat
The Common Vampire Bat is a small leaf-nosed bat native to the Americas. It is one of three extant species of vampire bat, the other two being the Hairy-legged Vampire Bat and the White-winged Vampire Bat. Along with them, it is the only parasitic mammal. It mainly feeds on the blood of livestock...
may also have an infrared sensor on its nose. It has been found that birds and some other animals are tetrachromats and have the ability to see in the ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
down to 300 nanometers. Bees and dragonflies are also able to see in the ultraviolet.
Balance
Ctenophora have a balance receptor (a statocystStatocyst
The statocyst is a balance sensory receptor present in some aquatic invertebrates, including bivalves, cnidarians, echinoderms, cephalopods, and crustaceans. A similar structure is also found in Xenoturbella. The statocyst consists of a sac-like structure containing a mineralised mass and numerous...
) that works very differently from the mammalian's semi-circular canals.
Sensing gravity
Some plants (such as mustard) have genes that are necessary for the plant to sense the direction of gravity. If these genes are disabled by a mutation, a plant cannot grow upright.Not analogous to human senses
In addition, some animals have senses that humans do not, including the following:- ElectroreceptionElectroreceptionElectroreception is the biological ability to perceive natural electrical stimuli. It has been observed only in aquatic or amphibious animals, since water is a much better conductor than air. Electroreception is used in electrolocation and for electrocommunication.- Overview :Electroreception is...
(or electroception) is the ability to detect electric fieldElectric fieldIn physics, an electric field surrounds electrically charged particles and time-varying magnetic fields. The electric field depicts the force exerted on other electrically charged objects by the electrically charged particle the field is surrounding...
s. Several species of fish, sharkSharkSharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s, and rays have the capacity to sense changes in electric fields in their immediate vicinity. Some fish passively sense changing nearby electric fields; some generate their own weak electric fields, and sense the pattern of field potentials over their body surface; and some use these electric field generating and sensing capacities for social communication. The mechanisms by which electroceptive fish construct a spatial representation from very small differences in field potentials involve comparisons of spike latencies from different parts of the fish's body.
- The only orders of mammals that are known to demonstrate electroception are the dolphinDolphinDolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...
and monotremeMonotremeMonotremes are mammals that lay eggs instead of giving birth to live young like marsupials and placental mammals...
orders. Among these mammals, the platypusPlatypusThe platypus is a semi-aquatic mammal endemic to eastern Australia, including Tasmania. Together with the four species of echidna, it is one of the five extant species of monotremes, the only mammals that lay eggs instead of giving birth to live young...
has the most acute sense of electroception.
- Dolphins can detect electric fields in water using electroreceptors in vibrissal cryptsWhiskerWhisker may refer to:* an element of box plots* cat's whisker diode, a thin wire used as a contact on a crystal radio receiver* facial hair, hair on the face of a human* vibrissa, a hair on the face of a mammal, used for sensing the surroundings...
arrayed in pairs on its snout and which evolved from whisker motion sensors. These electroreceptors can detect electric fields as weak as 4.6 microvolts per centimeter, such as those generated by contracting muscles and pumping gills of potential prey. This permits the dolphin to locate prey from the seafloor where sediment limits visibility and echolocation.
- Body modificationBody modificationBody modification is the deliberate altering of the human body for any non-medical reason, such as aesthetics, sexual enhancement, a rite of passage, religious reasons, to display group membership or affiliation, to create body art, shock value, or self expression...
enthusiasts have experimented with magnetic implants to attempt to replicate this sense, however in general humans (and it is presumed other mammals) can detect electric fields only indirectly by detecting the effect they have on hairs. An electrically charged balloon, for instance, will exert a force on human arm hairs, which can be felt through tactition and identified as coming from a static charge (and not from wind or the like). This is however not electroception as it is a post-sensory cognitive action.
- MagnetoceptionMagnetoceptionMagnetoception is the ability to detect a magnetic field to perceive direction, altitude or location. This sense plays a role in the navigational abilities of several animal species and has been postulated as a method for animals to develop regional maps.Magnetoception is most commonly observed in...
(or magnetoreception) is the ability to detect the direction one is facing based on the Earth's magnetic fieldMagnetic fieldA magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
. Directional awareness is most commonly observed in birdBirdBirds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s. It has also been observed in insects such as beeBeeBees are flying insects closely related to wasps and ants, and are known for their role in pollination and for producing honey and beeswax. Bees are a monophyletic lineage within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila...
s. Although there is no dispute that this sense exists in many avianBirdBirds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s (it is essential to the navigational abilities of migratory birds), it is not a well-understood phenomenon. One study has found that cattle make use of magnetoception, as they tend to align themselves in a north-south direction. Magnetotactic bacteriaMagnetotactic bacteriaMagnetotactic bacteria are a polyphyletic group of bacteria discovered by Richard P. Blakemore in 1975, that orient along the magnetic field lines of Earth's magnetic field. To perform this task, these bacteria have organelles called magnetosomes that contain magnetic crystals...
build miniature magnets inside themselves and use them to determine their orientation relative to the Earth's magnetic field. The question of how useful magnetoception may be to human beings is subject of ongoing research.
- Pressure detection uses the organ of Weber, a system consisting of three appendages of vertebrae transferring changes in shape of the gas bladderGas bladderThe swim bladder, gas bladder, fish maw or air bladder is an internal gas-filled organ that contributes to the ability of a fish to control its buoyancy, and thus to stay at the current water depth without having to waste energy in swimming...
to the middle ear. It can be used to regulate the buoyancy of the fish. Fish like the weather fish and other loaches are also known to respond to low pressure areas but they lack a swim bladder.
- Current detection The lateral lineLateral lineThe lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...
in fish and aquatic forms of amphibians is a detection system of water currents, consisting mostly of vorticesVortexA vortex is a spinning, often turbulent,flow of fluid. Any spiral motion with closed streamlines is vortex flow. The motion of the fluid swirling rapidly around a center is called a vortex...
. The lateral line is also sensitive to low-frequency vibrations. The mechanoreceptors are hair cellHair cellHair cells are the sensory receptors of both the auditory system and the vestibular system in all vertebrates. In mammals, the auditory hair cells are located within the organ of Corti on a thin basilar membrane in the cochlea of the inner ear...
s, the same mechanoreceptors for vestibular sense and hearing. It is used primarily for navigation, hunting, and schooling. The receptors of the electrical sense are modified hair cells of the lateral line system.
- Polarized light direction/detection is used by bees to orient themselves, especially on cloudy days. CuttlefishCuttlefishCuttlefish are marine animals of the order Sepiida. They belong to the class Cephalopoda . Despite their name, cuttlefish are not fish but molluscs....
can also perceive the polarization of light. Most sighted humans can in fact learn to roughly detect large areas of polarization by an effect called Haidinger's brushHaidinger's brushHaidinger's brush is an entoptic phenomenon first described by Austrianphysicist Wilhelm Karl von Haidinger in 1844.Many people are able to perceive polarization of light....
, however this is considered an entoptic phenomenonEntoptic phenomenonEntoptic phenomena are visual effects whose source is within the eye itself. In Helmholtz's words:...
rather than a separate sense.
- Slit sensillaSlit sensillaThe slit sensilla is a small mechanoreceptory organ in the exoskeleton of spiders which detects strain due to forces experienced by the animal. As the name indicates, a slit sensilla is a small groove in the exoskeleton which deforms under stress, and these deformations are detected by neurons...
e of spiders detect mechanical strain in the exoskeleton, providing information on force and vibrations.
Plant senses
Some plants have sensory organs, for example the Venus fly trap, that respond to vibration, light, water, scents, or other specific chemicals. Some plants sense the location of other plants and attack and eat part of them.Culture
The traditional five senses are enumerated as the "five material faculties" () in Buddhist literature. They appear in allegorical representation as early as in the Katha UpanishadKatha Upanishad
The Katha Upanishad , also titled "Death as Teacher", is one of the mukhya Upanishads commented upon by Shankara. It is associated with the school of the Black Yajurveda, and is grouped with the Sutra period of Vedic Sanskrit. It is a middle Upanishad...
(roughly 6th century BC), as five horses drawing the "chariot
Chariot
The chariot is a type of horse carriage used in both peace and war as the chief vehicle of many ancient peoples. Ox carts, proto-chariots, were built by the Proto-Indo-Europeans and also built in Mesopotamia as early as 3000 BC. The original horse chariot was a fast, light, open, two wheeled...
" of the body, guided by the mind as "chariot driver".
Depictions of the five traditional senses as allegory
Allegory
Allegory is a demonstrative form of representation explaining meaning other than the words that are spoken. Allegory communicates its message by means of symbolic figures, actions or symbolic representation...
became a popular subject for seventeenth-century artists, especially among Dutch
Dutch Golden Age painting
Dutch Golden Age painting is the painting of the Dutch Golden Age, a period in Dutch history generally spanning the 17th century, during and after the later part of the Eighty Years War for Dutch independence. The new Dutch Republic was the most prosperous nation in Europe, and led European trade,...
and Flemish Baroque painters. A typical example is Gérard de Lairesse
Gerard de Lairesse
Gerard or Gérard de Lairesse was a Dutch Golden Age painter and art theorist.Lairesse was born in Liège. His broad range of talent included music, poetry, and the theatre. He was perhaps the most celebrated Dutch painter in the period following the death of Rembrandt...
's Allegory of the Five Senses (1668), in which each of the figures in the main group allude to a sense: Sight is the reclining boy with a convex mirror, hearing is the cupid
Cupid
In Roman mythology, Cupid is the god of desire, affection and erotic love. He is the son of the goddess Venus and the god Mars. His Greek counterpart is Eros...
-like boy with a triangle
Triangle (instrument)
The triangle is an idiophone type of musical instrument in the percussion family. It is a bar of metal, usually steel but sometimes other metals like beryllium copper, bent into a triangle shape. The instrument is usually held by a loop of some form of thread or wire at the top curve...
, smell is represented by the girl with flowers, taste is represented by the woman with the fruit, and touch is represented by the woman holding the bird.
See also
- AttentionAttentionAttention is the cognitive process of paying attention to one aspect of the environment while ignoring others. Attention is one of the most intensely studied topics within psychology and cognitive neuroscience....
- ApperceptionApperceptionApperception is any of several aspects of perception and consciousness in such fields as psychology, philosophy and epistemology.-Meaning in psychology:...
- Āyatana (Sense Bases in Theravada Buddhism)
- Basic tastes
- ChemesthesisChemesthesisChemesthesis is defined as the chemical sensibility of the skin and mucus membranes. Chemesthetic sensations arise when chemical compounds activate receptors associated with other senses that mediate pain, touch, and thermal perception. These chemical-induced reactions do not fit into the...
- CommunicationCommunicationCommunication is the activity of conveying meaningful information. Communication requires a sender, a message, and an intended recipient, although the receiver need not be present or aware of the sender's intent to communicate at the time of communication; thus communication can occur across vast...
- EmpiricismEmpiricismEmpiricism is a theory of knowledge that asserts that knowledge comes only or primarily via sensory experience. One of several views of epistemology, the study of human knowledge, along with rationalism, idealism and historicism, empiricism emphasizes the role of experience and evidence,...
- Extrasensory perception
- HypersensitivityHypersensitivityHypersensitivity refers to undesirable reactions produced by the normal immune system, including allergies and autoimmunity. These reactions may be damaging, uncomfortable, or occasionally fatal. Hypersensitivity reactions require a pre-sensitized state of the host. The four-group classification...
(people with unusual sense abilities)- Human echolocationHuman echolocationHuman echolocation is the ability of humans to detect objects in their environment by sensing echoes from those objects. By actively creating sounds – for example, by tapping their canes, lightly stomping their foot or making clicking noises with their mouths – people trained to orientate with...
- SupertasterSupertasterA supertaster is a person who experiences the sense of taste with far greater intensity than average. Women are more likely to be supertasters, as are individuals of Asian and African descent. The cause of this heightened response is currently unknown, although it is thought to be, at least in...
- Vision-relatedEntoptic phenomenonEntoptic phenomena are visual effects whose source is within the eye itself. In Helmholtz's words:...
:- Haidinger's brushHaidinger's brushHaidinger's brush is an entoptic phenomenon first described by Austrianphysicist Wilhelm Karl von Haidinger in 1844.Many people are able to perceive polarization of light....
(ordinary people sensing light polarisation) - TetrachromatTetrachromatTetrachromacy is the condition of possessing four independent channels for conveying color information, or possessing four different types of cone cells in the eye...
(increased colour perception)
- Haidinger's brush
- Human echolocation
- IllusionIllusionAn illusion is a distortion of the senses, revealing how the brain normally organizes and interprets sensory stimulation. While illusions distort reality, they are generally shared by most people....
s- Auditory illusionAuditory illusionAn auditory illusion is an illusion of hearing, the aural equivalent of an optical illusion: the listener hears either sounds which are not present in the stimulus, or "impossible" sounds...
- Optical illusionOptical illusionAn optical illusion is characterized by visually perceived images that differ from objective reality. The information gathered by the eye is processed in the brain to give a perception that does not tally with a physical measurement of the stimulus source...
- Touch illusionTouch illusionTactile illusions are illusions that exploit the sense of touch. Some touch illusions require active touch , whereas others can be evoked passively .-Examples:...
- Auditory illusion
- IntuitionIntuition (knowledge)Intuition is the ability to acquire knowledge without inference or the use of reason. "The word 'intuition' comes from the Latin word 'intueri', which is often roughly translated as meaning 'to look inside'’ or 'to contemplate'." Intuition provides us with beliefs that we cannot necessarily justify...
- Multimodal integrationMultimodal integrationMultimodal integration, also known as multisensory integration, is the study of how information from the different sensory modalities, such as sight, sound, touch, smell, self-motion and taste, may be integrated by the nervous system. A coherent representation of objects combining modalities...
- PerceptionPerceptionPerception is the process of attaining awareness or understanding of the environment by organizing and interpreting sensory information. All perception involves signals in the nervous system, which in turn result from physical stimulation of the sense organs...
- Phantom limbPhantom limbA phantom limb is the sensation that an amputated or missing limb is still attached to the body and is moving appropriately with other body parts. 2 out of 3 combat veterans report this feeling. Approximately 60 to 80% of individuals with an amputation experience phantom sensations in their...
- Remote sensingRemote sensingRemote sensing is the acquisition of information about an object or phenomenon, without making physical contact with the object. In modern usage, the term generally refers to the use of aerial sensor technologies to detect and classify objects on Earth by means of propagated signals Remote sensing...
- SaḷāyatanaSadayatana' or ' means the six sense bases , that is, the sense organs and their objects. These are: is the fifth link in the Twelve Nidānas of Pratitya-Samutpada and thus likewise in the fifth position on the Bhavacakra...
and Ayatana (the six senses as a concept in BuddhismBuddhismBuddhism is a religion and philosophy encompassing a variety of traditions, beliefs and practices, largely based on teachings attributed to Siddhartha Gautama, commonly known as the Buddha . The Buddha lived and taught in the northeastern Indian subcontinent some time between the 6th and 4th...
) - Sensation and perception psychologySensation and perception psychologyIn psychology, sensation and perception are stages of processing of the senses in human and animal systems, such as vision, auditory, vestibular, and pain senses. These topics are considered part of psychology, and not anatomy or physiology, because processes in the brain so greatly affect the...
- Sense of time
- Sensitivity (human)Sensitivity (human)The sensitivity or insensitivity of a human, often considered with regard to a particular kind of stimulus, is the strength of the feeling it results in, in comparison with the strength of the stimulus...
- SensoriumSensoriumThe term sensorium refers to the sum of an organism's perception, the "seat of sensation" where it experiences and interprets the environments within which it lives. The term originally enters English from the Late Latin in the mid-17th century, from the stem sens-...
- Sensory Processing DisorderSensory processing disorderSensory processing disorder or SPD is a neurological disorder causing difficulties with taking in, processing and responding to sensory information about the environment and from within the own body .For those with SPD, sensory information may be sensed and perceived in a way that is different from...
- Sensory systemSensory systemA sensory system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory receptors, neural pathways, and parts of the brain involved in sensory perception. Commonly recognized sensory systems are those for vision, hearing, somatic...
- SynesthesiaSynesthesiaSynesthesia , from the ancient Greek , "together," and , "sensation," is a neurologically based condition in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway...
External links
- The 2004 Nobel PrizeNobel PrizeThe Nobel Prizes are annual international awards bestowed by Scandinavian committees in recognition of cultural and scientific advances. The will of the Swedish chemist Alfred Nobel, the inventor of dynamite, established the prizes in 1895...
in Physiology or MedicineNobel Prize in Physiology or MedicineThe Nobel Prize in Physiology or Medicine administered by the Nobel Foundation, is awarded once a year for outstanding discoveries in the field of life science and medicine. It is one of five Nobel Prizes established in 1895 by Swedish chemist Alfred Nobel, the inventor of dynamite, in his will...
(announced 4 October 2004) was won by Richard AxelRichard AxelRichard Axel is an American neuroscientist whose work on the olfactory system won him and Linda B. Buck, a former post-doctoral scientist in his research group, the Nobel Prize in Physiology or Medicine in 2004....
and Linda Buck for their work explaining olfaction, published first in a joint paper in 1991 that described the very large family of about one thousand genes for odorant receptors and how the receptors link to the brain. - Answers to several questions related to senses and human feeling from curious kids
- The Physiology of the Senses tutorial 12 animated chapters on vision, hearing, touch, balance and memory.